Production of vat dyestuffs



Patented Jan. 19, 1932 UNE'E'ED STATES PATENT OFFICE MAX ALBERT KUNZ, OF MAN NHEIM, AND KARL KOIBERLE, OF LUDWIGSHAFEN-ON-THE- RHINE, GERMANY, ASSIG-NOE-S TO GENERAL ANILINE WORKS, INC., OF NEW YORK,

N. Y., A. CORPORATION OF DELAWARE PRODUCTION OF VAT DYESTUFFS No Drawing. Original application filed June 16, 1927, Serial No. 199,420, and in Germany July 21, 1926.

Divided and this application filed The subject matter of the present application has been divided out from our copending application for the manufacture of vat dyestuffs, Ser. No. 199,420, filed June 16,

1927, and relates to the manufacture of vat dyestuffs which are considered to be ms-anthradianthrones.

We have found that particularly valuable vat dyestuffs are obtained by subjecting alloins-naphthodianthrone or derivatives thereof obtainable according to our copending application Ser. No. 199,420 in acid solution to the action of oxidizing agents such as lead dioxid, manganese dioxid, nitric acid and the like. It is probable that by the said treatment condensation is effected with additional ring formation according to the formulae:

Example 1 part of manganese dioxid is stirred, at ordinary temperature into the solution of 1 part of allo-ms-naphthodianthrone in parts of concentrated sulfuric acid. Stirring 59 is continued until the color of the solution July 28, 1928. Serial No. 296,087.

has changed from green to a pure violet and after filtering by suction the filtrate is precipitated with ice. The resulting brown reaction product is identical with the dyestuif described in Example 1 of our copending application Ser. No. 296,088. It crystallizes from nitrobenzene in yellowish brown needles, dissolving to a violet solution in concentrated sulfuric acid, and dyes cotton from a bluish violet vat strong golden yellow shades.

The manganese dioxid may be replaced by lead dioxid, saltpetre, lead tetra-acetate or similar oxidizing agents.

What we claim is Y 1. The process of producing new vat dyestuffs which comprises subjecting an allo-msnaphthodianthrone in acid solution to the action of an oxidizing agent.

2. The process of producing new vat dyestuffs which comprises subjecting a halogenated allo-ms-naphthodianthrone in acid solution to the action of an oxidizing agent.

3. The process of producing new vat dyestuifs which comprises subjecting an allo-msnaphthodianthrone in sulfuric acid solution to the action of manganese dioxid.

4. As a new article of manufacture the vat dyestufi which is considered to be ms-anthradianthrone corresponding to the formula:

0 II o crystallizing from nitrobenzene in yellowish brown needles, dissolving to a violet solution in concentrated sulfuric acid and dyeing cotton from a bluish violet vat strong golden yellow shades.

In testimony whereof, we aflix our signatures.

MAX ALBERT KUNZ.

KARL KOBERLE. 

